BIOSC 150 1nd Edition Lecture 19Outline of Last Lecture I. GeneticsII. OffspringIII. InheritanceOutline of Current Lecture 1. Meiosis I2. Meiosis II3. Sexual ReproductionCurrent LectureMeiosis- making haploid gametes-Meiosis explains Mendel’s principals of segregation and independent assortment-Members of gene pair (alleles) segregate into different gametes-Alleles for different genes sort independently of each other into gametes Sexual Reproduction:-Produce haploid gametes through meiosis-Fertilization fusing haploid gametes to form a diploid zygote-Mitotic divisions to make many diploid cells that will differentiate and develop a new organism-Meiosis makes cells that become sperm or eggs in testes or ovaries-Oocytes begin meiosis in fetal ovaries and then stop until puberty (6-12 months)-Chromosomes do not “hang out” in pairs like this but Nettie Stevens noticed 2 of each chromosome size/ shape-Number of chromosomes varies in different organisms These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-Homologues have the same genes in same place but often have different alleles of the gene-Non-homologues chromosomes contain different genes-Gametes contain one copy of each chromosome (Other cells will contain two)-DNA replicates before meiosis-Recombination sorts some alleles between homologues-Homologues pair, align, and separate in meiosis I-Sisters separate in Meiosis II-Homologues orient randomly at equator-Mating brings the sperm and egg together-Mitotic divisions follow gamete nuclei fusion-Homologues chromosomes pair, line up and separate in Meiosis
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